Emissions control systems for industrial engines, particularly large, stationary, reciprocating engines, commonly include catalytic converters having removable catalyst elements. The use of removable elements allows periodic inspection, cleaning, and replacement of the catalyst elements without removing or replacing the catalytic converter housing.
A catalytic converter assembly 1 of the type heretofore used in the art, as well as a removable catalyst element 4 therefor, are depicted in FIGS. 1 and 2. The catalytic converter assembly 1 comprises: a housing 2 wherein one or more (typically a plurality) of the catalyst elements 4 are removably received; a pair of flanges or other connections 3 provided on the longitudinal ends of housing 2 for installing the catalytic converter assembly 1 in an engine exhaust system; an exhaust gas flow passage 5 extending longitudinally through the housing 2; an insertion channel 6 projecting from and extending laterally across housing 2 for inserting the catalyst element(s) 4 into housing 2 such that the element(s) 4 extend laterally across the exhaust flow passage 5; and a cover 8 removably secured on the outer end of insertion channel 6 for closing the converter assembly 1. The catalyst element 4 and the lateral interior cross section of the converter housing 2 have corresponding octagonal shapes.
Unfortunately, a common problem with the catalytic converter assemblies heretofore used in the art is that it has been difficult to achieve and maintain an adequate seal around the perimeter of the catalyst element(s) 4. In this regard, it has been particularly difficult to adequately ensure that exhaust gas does not bypass the catalyst element(s) 4 by flowing into the insertion channel 6 and over the top of the element(s) 4. When exhaust gas bypasses the catalyst element(s) 4, the exhaust stream is not adequately clean and pollutant emissions can be significantly higher than desired.
The approach used heretofore for attempting to seal the insertion channel 6 to prevent exhaust gas from flowing over the top of the catalyst element(s) 4 has typically involved installing a heat resistant padding or mat material in the insertion channel 6 above catalyst element(s) 4. However, the use of a padding or mat material of this type has not been sufficiently effective or reliable.